Chapter 6 - Preparation of the area of installation before the implant surgery
Director of Tokyo Kagawa Dental Clinic
Toshiaki Miyazawa
For a smooth implant surgery and to improve prognosis, it is necessary to prepare the area of treatment
suitable for operation. In this chapter, I will discuss the preoperative surgical procedures, intraoraltreatment, periodontal disease treatment, occlusal treatment and orthodontic treatment.
I.

Preoperative surgical procedure

A.

Points to consider in tooth extraction

Tooth extraction should be conducted to minimize bone resorption, a common complication to arise fromthe extraction procedure.
1.

Points when undergoing general tooth extraction

Conduct tooth extraction procedures in the usual manner and limiting the damage to the jaw bone of theextraction cavity with mainly using forceps. Other important points are to ensure complete removal ofinfection foci, cysts and infected granulation tissues.
The use of typical hemostatic materials should be avoided such as oxycellulose and surgical (oxidizedcellulose), and spongel (gelatin sponge) since these can delay the healing of the extraction cavity or
prevent bone regeneration process. The bullet-type atelocollagen sponge (Teruplug, Terumo Corporations,Fig. 2-6-1) specifically designed for the tooth extracted sockets, effective for preventing bone resorption,pain and bleeding 1) after the extraction should be used instead.

Fig. 2-6-1-a,b Teruplug (Terumo Corporation)
2. Point to consider for immediate loading
Immediate loading2) is where implant installation is conducted straight after tooth extraction. This
technique was developed as a method to minimize the bone resorption. The complication was found toprogress with time after the tooth extraction that subsequently led to the difficulty in the implantationand limitations. This method however has its drawbacks as well as its advantages 3).
Advantages:


Where two stages of surgical intervention is usually necessary, with this method, it can be completed
in one step.

Treatment period can be shortened.

Disadvantages:


Where the complete removal of the infection foci was not possible, or in some bone structures, theimplant installation or the stabilization can be made difficult.

The suturing accuracy of the gingivae cannot always be achieved.

There are four criteria to fulfill for undertaking the immediate loading① Primary stability can be achieved safely.
② Insert the implant, 2 mm deeper than usual.
③ Epithelium can be stopped from invading into the internal structures.
④ Ensure that the space between the implant and the extraction cavity to be within 2 mm, or otherwise
fill the space with bone graft materials.
It should be noted however, that even if the above criteria are met, it does not always indicate that thismethod is suitable. With regards to AQB implants that have been coated with a layer of HA, theconfirmation that this coating layer has been fully enclosed within the bone is not possible with thismethod. The presentation of the symptoms as a result of the HA-layer exposure does not show within ashort duration of time, but has been reported to take more than five years. There have also been studies
that have indicated bone resorption to be a complication that inevitably occurs with the immediateloading method, thus leading to a conclusion that this technique must be employed carefully, and that not
all cases are appropriate for this method.
Although the statics suggest that the success rates of the immediate loading to be 90%3), if the above
factors are considered, especially with the concern of the HA coating layer of AQB implant, either limiting
its use, or alternatively await the healing process with application of Teruplug into the extraction cavity
before undergoing the usual implant method.
B. Improving the state of gingival alveolar mucosa
The ideal type of mucosa to surround the implant is the attached gingivae (keratinized type), especiallyin terms of periodontology, in that it has excellent sealing abilities around the implant cervix. In thischapter, I will discuss the vestibular extension procedure and frenectomy, which are the two
representatives of surgical methods of gingival alveolar mucosa.
1. Oral vestibular extension procedures
The incision should only be applied to the area of attached gingivae (keratinized gingivae) remaining,
and leaving the periosteal flap on top of the periosteum. Perform incision elevation in a way of forming
partial thickness flap, peel down the gingivae in the apical direction, and suture the segment with theperiosteum. This procedure should enable improved plaque control by the widening of the width ofattached gingivae and the expansion in the oral vestibule, therefore improving the overall hygiene of theoral cavity.
2. Frenectomy
This is a surgery to correct the attachment height of the frenulum. In conditions in which the frenulum isattached at an unusually high position, the width of the attached gingivae becomes narrower. The
problem with this is that the contraction of the frenulum during the jaw movement leads exertion ofexcessive tension and leading to gingival traction. This consequently prevents stabilization of thesurrounding gingival structures and effective plaque control. Therefore this preparative operation should
not be neglected to facilitate the success of implant surgery.
C. Improving the state of alveolar crest
In order to lengthen the functional time of the implant and its survival, the occlusal conditions including:
distribution, equality, and the directionality of the occlusal force applied are important factors to beconsidered. The key factors in determining the occlusal force, the installation position and its direction,
are completely influenced by the state of the alveolar ridge. Thus the necessity of the preparation of thealveolar ridge is obvious in order to improve the prognosis of the implant treatment.
The implant is usually installed to the area of the bone where the quantity is sufficient. But often resultsin the installation to the lingual side, as the bone resorption on the buccal side is usually more significant.
The superstructure thus becomes placed as a cantilever on the buccal side. The lateral forces become
greater with such structure and can subsequently lead to the development of severe complications later
on. Therefore for such cases, the top-to-bottom treatment scheme may be more appropriate, that places
the prime importance on the selection of the prosthesis and allows the adjustment of the alveolar bone
structure by the application of GBR techniques.
While on the subject of implant installation arrangement, in the previous practices where three implants
were placed next to each other, the central implant was consciously displaced from the row of three, which
was referred to as the off-set alignment. By adopting this technique, the implant installation wasconducted without any preparative measures made on the alveolar bone, and the location was chosen
simply on where a sufficient bone quantity was present. Therefore the placement of the implants tended
to be on the palatal side in the maxilla, and to the buccal side in the mandibular, without any
considerations to the occlusal relationships. The general consensus was that the misalignment in theseries of installation was even better, but was soon contradicted. The reason for such implantation
method was derived from two-dimensional analysis and it had not implemented the three-dimensional
aspect. This was deemed unreliable, raised issues of the superstructure becoming a cantilever structureby the off-set arrangement; or that the occlusal plane of the superstructure did not always settle within
the range of loading support that is constructed by the straight line that converge at the centre of theimplanted body. As a result, the preferred alignment at present is with the in-line arrangement, which isalso suitable in terms of the esthetics.
It can be concluded that in order to achieve a correct occlusion, the stability of the alveolar ridge is ofparticular importance, therefore within the treatment plan, the preparation of the state of alveolar ridgeis necessary, that includes the superstructure design, and the surgical procedures to facilitate the implantinstallation. Alveolar alveoplasty, GBR, ridge-expansion or distraction are the common procedures toarrange the alveolar bone structure.
D. Maxillary floor elevation
The most important point to consider when conducting implant to the maxillary anterior region, isevidently the positional relationship with the maxillary sinus. Bone quantity is often insufficient forimplant installation in the areas where there is a significant bone resorption that resulted from toothextraction, or where the baseline of maxillary sinus is below the standard. Commonly, in such cases, themethod has been adopted to graft the bone into the space that has been created by the elevation of theschneiderian membrane from the cortical bone floor of the maxillary sinus. There are sinus-lift andsocket-lift techniques. For further details regarding these techniques, refer to Part 6 of this text.
1.

Sinus-lift (Fig. 2-6-2) 7)

Punch a hole on the lateral wall of the maxillary sinus to allow access to the maxillary sinus interior. This
technique is typically applied to cases where the the bones are within 5 mm in height.
Advantages:
Allow direct visualization - reliable surgery can be conducted

Necessary amounts of bone graft material for the elevation of the maxillary sinus can be applied

Disadvantages:


Relatively large surgical invasionThe healing period is long (approx. three to six months) even if the implant has been inserted at thesame timeThe grafted bone could be subjected to bone resoprtion

2.

Socket-lift (Fig.2-6-3) 8)

Typically applied to the cases where the height of the bone is more than 5 mm.
Advantages:
Extent of surgical invasion is significantly less than that of the sinus-lift procedure

Disadvantages:


There is a risk of perforating the schneiderian membrane when hammering with osteotome.

There is a limit to the extent that the maxillary sinus floor can be elevated.

Fig.2-6-2 Sinus-lift procedureE.

Fig.2-6-3 Socket-lift procedure

Examination at the point of installation

It is fundamental to stay true to the basics when conducting the installation. Accurate information
including bone quantity and the bone density alongside grasping the anatomical locations of the nasal
cavity, maxillary sinus, and the mandibular canal in a three dimensional form, should be obtained using
as much analysis tools as possible, before the operation.
The application of CT, which has become the mainstream tool in the examination and diagnosis in thefield of dental surgery, not only has enabled the bone quantity and density to be determined accurately,
but also enabled the picture to be displayed in 3D form as well as the simulation of the treatment prior tothe actual procedure.
The placement of implant should be conducted with the utmost care, applying the detailed treatment plan
constructed with the implementation of the above factors.

References
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106: 38-44. (in Japanese)
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regarding the placement of implants in extraction sockets. Int J Oral Maxillofac Implants 2004; 19: 26-28.
4) Lazzara RJ: Immediate implant placement into extraction sites:surgical and restorative advatages. Int
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6) Botticelli D, Berglundh T, Lindhe J: Resolution of bone defects of varying dimension and configurationin the marginal portion of the peri-implant bone. An experimental study in the dog. J Clin Periodontol
2004; 31(4): 309-17.
7) Boyne PJ, James RA: Grafting of the maxillary sinus floor with autogenous marrow and bone.
8) Summers RB: A new concept in maxillary implant surgery:the osteotome technique. Compendium
1994; 15(2): 152,154-6,158.